Abstract:
Aim: An RNA-seq analysis recently identified a 236-nucleotide transcript
upstream from malS in Salmonella enterica serovar Typhi. Here, we investigated its molecular
characteristics and function. Materials & methods: RACE and northern blotting were used
to determine the molecular characteristics of the sequence, and mutagenesis, microarray,
immunoblotting and an invasion assay were used to investigate the functions of the
transcript. Results: The transcript was identified as the malS 5′-untranslated region (UTR),
which could influence the expression of the flagellar and SPI-1 genes and the invasion of
HeLa cells by S. Typhi. Deletion of bax increased the expression of the invasion genes and
the invasive capacity of S. Typhi, whereas the expression of the malS 5′-UTR reduced the
expression of bax. Conclusion: The malS 5′-UTR reduces the expression of bax and increases
the invasive capacity of S. Typhi.
